In the seemingly perpetual battle against infection by pathogenic microorganisms, a recent, alarming trend has been observed. Antibiotic medications and treatments long thought to have conquered, if not arrested, the invasive infection of humans by such pathogens (generally, prokaryotic organisms, such as bacteria), have recently begun to fail or lose effectiveness at stopping such infections. Terrifying, and seemingly increasingly frequent, news stories of either fatal or serious infection by such bacteria as the common intestinal inhabitant Escherichia coli 0.157 (especially affecting small children and those with a lesser, or challenged immune system), and by certain species of Staphylococcus sp. (colorfully, but somewhat inaccurately dubbed in news accounts as "flesh eating bacteria") have led to the conclusion that prevention, by decontamination of surfaces touched by humans, may indeed be a wiser remedy than cure by antibiotics. So, the search for appropriate antimicrobial treatments of surfaces is spurred by this new challenge by these old enemies of the human population.
The use of quaternary ammonium compounds as antimicrobial agents is well known in the art. See U.S. Pat. Nos. 2,746,928, 3,344,018, 3,719,711, and JP 01/046081. For instance, quaternary ammonium compounds have been incorporated into polymer and liquid compositions to protect the compositions themselves from microbial attack (i.e., used as preservatives). See U.S. Pat. Nos. 3,471,423, 5,028,619 and 5,399,343. Furthermore, quaternary ammonium compounds have also been employed as an additive in a variety of household products including detergents. See U.S. Pat. Nos. 3,093,591, 3,560,390, 4,272,395 and 4,576,729.
An effort to remedy the issues faced by prior antimicrobial compositions was posed in the commonly owned U.S. patent application Ser. No. 08/833,276, filed Apr. 4, 1997, of Boli Zhou et al., the disclosure of which is incorporated herein by reference. This Patent Application contemplated the formation of a novel mixed anionic/cationic polymer having residual antimicrobial efficacy. However, the application did not disclose, suggest or teach that an aerosol composition containing a mixture of an anionic polymer and a quaternary ammonium compound has both disinfectancy (contact efficacy) and residual antimicrobial efficacy. There are also various compositions, especially hard surface cleaners, which have been delivered as aerosols but which do not contain the inventive mixture of an anionic polymer and a quaternary ammonium compound having both disinfectancy (contact efficacy) and residual antimicrobial efficacy.